Yarn-controlled stopping device for knitting machines



Feb. 23, 1954 YARN-CONTROLLED STOPPING B. LEBOCEY 2,669,855

DEVICE FOR KNITTING MACHINES Filed Nov. 20, 1951 In wen/0 Ber/7 rd Lebaccy I 8 connected to the anode I8 into engagement Patented Feb. 23, 1954 7 UNITED .sTATEs PATENT OFFICE YARN-CONTROLLED STOPPING DEVICE FOR KNITTING MACHINES Claims priority, application France November 24, 1950 5 Claims.

A particular embodiment of the device according to this invention will be described hereinafter for the purpose of exemplification and by no means of limitation, reference being had to the appended drawing which shows the wiring diagram relating to the described embodiment.

- The drop wire I consists of a thin wire formed at its free end with a hook which rests on the yarn 2 while its portion located in the vicinity of the opposite end is hinged about a horizontal pivot 3 mounted at right angles to the plane of the drawing.

As shown in the appended drawingthe swingable drop wire I resting on the yarn 2 fed to the frame is earthed through its pivot 3 or in any other manner and through a lead 4. In normal working position the free end 5 of the drop wire .is out of contact with an insulated and suitably supported lead 6. Same is connected with the grid I6 of a thermionic valve 1 which is a gas filled electronic relay, the connexion being effected through a condenser I9 and a resistor 26 of comparatively low value. Said valve i performs the function of an instantaneous electronic relay between the input circuit and the circuit for the energization of the electromagnet coil and the cathode. ii of the thermionic valve.

As soon as the yarn 2 fed to the machine hap- .pens to fail under the hook of the drop wire i -Its free end 5 isthereby swung thelatter drops.

with the terminal 9 of the lead 6 which is thereby earthed contingently through the machine.

In addition, said grid I6 is connected through a resistor ll! of comparatively high value to the biassing potentiometer II.

Said potentiometer I l is fed with rectified current from a transformer I2 through a push-pull rectifier I3 with the interposition of a pair of resistors I4, I 5 the values of which are determined in dependency on the characteristics of the rectifier and on the voltage to be impressed upon the grid I6 of the thermionic valve I.

By means of the adjustable potentiometer H, with the machine working normally, the grid #6 of the valve l is biassed negatively so as to check the flow from cathode I I to anode I8. In this manner the condenser I9 remains loaded as long as the lead 6 is not earthed.

Upon said lead 6 being earthed consequent to the drop of the drop wire I the condenser I9 is unloaded. Owing to the comparatively high ratio between the values. of resistors Ill and 20 such a discharge leads to an instantaneous variation in the grid potential, the curve of which sinks to zero. The balance between the potentials of cathode I! and grid I6 is thus upset and the valve is primed.

The input circuit of the electromagnet coil 8 is closed through the valve I. Said electromagnet 8, of conventional design, becomes effective to instantaneously bring the machine to stand still. The responsivity of the electronic relay can be adjusted with the aid of the condenser 2| which provides for the electrostatic connection between the cathode H, the grid I6 and earth. Anyhow, the voltage of condenser 2| remains higher than the voltage of condenser [9.

A condenser 22 interposed in known manner between grid Iii and cathode I I is provided for the purpose of stabilizing the grid potential in the event variations should occur in the anode current which might lead to an unexpected priming of the valve.

It will be noticed that in this embodiment which is given by way of example the circuits for the biassing and the loading of the valve are separated from the network by the transformer I2 to the primary winding of which current is only fed when the machine is running.

For the sake of safety in operation and reliability in control it is particularly expedient to make it practically impossible to start the machine for the time the valve is heated in. Effectively, it need not be emphasized that the electronic relay must be ready to operate as soon as the" machine. is started. With this end in view,

system oi delaying relays is provided which will be described later on with reference to the drawing.

Moreover, it is also important to stop the machine automatically or to prevent its being restarted whenever the filament of the thermionic valve happens to break.

According, auxiliary circuits may be provided for the sake of safety. A particular embodiment of such improvements is illustrated in the drawmg.

i3, 24, 25 designate the three leads of the genera} power system.

Said leads are connected with the motor control automatic switch through a section switch the holding coil 29 of which is energized by the primary winding of the transformer 21.

A 2-pole switch 28 provides for the energization of the coil 2% of said section switch 26.

As soon as the transformer 21 is thrown into circuit the current that flows through its secondary winding provides for the heating up of the filament 3B of the thermionic valve 1; however, the operation of the sectionrelay2'6 isdelayed by the functioning of suitable relays '3! 32.

Said relays 3!, 32 may simply consist of a pair of conventional discharge lamp starters connected in series in the supply line for coil 29.

Each of these relays comprises a raregas tube, which is generally a neon tube, inside which is mounted a bimetallic strip adapted to engage a contact when heated. When a sufiioient'tension is applied between said strip and said contact, the ionized gas causes a sufiicient heating'of the stripto make it engage the contact and thus-close the relay. In the embodiment shown in the drawing, the relay '32 is byepassed by a resistor 33 which filSl) causes the relay-3i to ionize and close, whereaft-cr relay .82 in its turn will iclos'e with a definite lag which depends on the value of a resistor which is connected in shunt relative thereto. The delay thus brought about in the throwing .in of thesection switch25 is sufficient to enable the cathode H to heat'up before the frame can be switched in.

Connected with the secondary winding of transformer 2? is also a coil 3 5 which serves to hold the automatic motor control switch (not shown).

The operation of said automatic motor-control switch is arranged subject to the closing of the circuit through which coil 3 is supplied with current. Such a closing is ensured on theone hand by the throwing into engagement of the arm 35 actuated by a relay 3'5 connected inseries with the current-supply circuit for the filament 3d and on the other hand by means of'a starting push 31.

A plurality of such pushes 3i may be'arrange'd at several placescn the'machine in order that the switch kid can be thrownin, and consequently the machine set into operation inthe best-possible ,1,

conditions.

The supply of current to the machine is'c'ontrolled as follows bythe filament circuit:

As soon as the circuit through filament 3i) happens to be broken relay wil1 release the arm 35, whereb the motor control switch holding circuit through. coil 3d is likewise broken and the machine is stopped automatically.

What I claim is:

1. A device for automatically stopping a knitting machine whenever the yarn'happ'ens to be broken, which device comprises an electronicrelay of the gaseous atmosphere type, an electroinagnet adapted to stop the knitting machine when energized and having its energizing circuit inserted in the anode circuit of said relay, means for causing a continuous negative'biassing of the grid of said relay, and a'drop wire having a rest on the yarn and adapted to cause an instantaneous variation of the potential of the grid whenever said rest comes to fail.

2. A device forautomatically stopping a knitting machine whenever the yarn happens to be broken, which device comprises an electronicrelay of the gaseous atmosphere type, an electromagnet adapted to stop the knitting machine when energized and having its energizing circuit inserted in the anode circuit of said relay,

means for negatively biassing the grid of said relay, a condenser having one armature con nected to said grid, and a drop wire having a rest on the yarn and adapted to earth the other armature of said condenser whenever said rest comes to fail, thereby unloading the condenser and causing the'grid to let a current flow through the anode circuit, which current energizes the electromagnet and causes the knitting machine to stop.

3. -A device for automatically stopping a knitting machine whenever the yarn happens to be brokemWhich device comprises an electronic relay of the gaseous atmosphere type, an electromagnet adapted to stop the knitting machine when energized and having its energizing circuit inserted in the anodc circuit of said relay, a rectifier a biasing circuit connecting said rectifier tothegrid of the relay and adapted to bias negatively'said grid,acondenser having one armature connected to said grid, and a drop wire having arestonthe yarn and adapted'to earth the other armature .of said condenser whenever said re'st comes to fail, thereby unloading the condenser and causing the grid'to let a currentflow through the anode circuit, which current energizes the electromagnet and causes the knitting machine to stop.

4. A device for automatically stopping a -knitting machine whenever the yarn 'hambens to be broken, which device comprises an electronic relay of the gaseous atmosphere type, an electromagnet adapted to stop the knitting machine when'energizedand having its energizing circuit inserted in-theanode circuit 'of said relay, means for causing a continuous negative biassing of the grid of said relay, ta drop wire having arrest onthe yarn and adapted to'caus'e'an instantaneous variation of thetpotential of the 'grid whenever :said rest'comes "to fail, and anauxiliary relay in the filament circuit adapted to :stop the machine in the event the currentfshouid rail to flow through said filament consequent to the breakage of the 'sa'rne.

5. .A device for automatically stopping a knitting machine whenever the yarn happens to be broken, which device'comprises an electronic'relay of thegaseous atmosphere type, an electromagnet adapted to stop the knitting machine when energized "and having its energizing circuit inserted in-the anode circuit of said relay, means for causing acon'tinuous negativelbiassing of'thegrid of'sa'id relay, a condenser having one armature connected to said grid, a dro wire having a rest on the yarn and adapted to earth the'othe'r a'rmature'of said condenser whenever said rest comes to fail, thereby unloading the condenser, causing the g'ri'd'to let a currentiiow through the anode -.circuit, energizing thus the electromagnet and causing the knitting machine to stop, and time relays adapted to delay the starting of the machine up to sufficient heating of the electronic relay.

BERNARD LEBO'C'EY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,383,838 Auble -i Aug. 28, 15 945 2,436,023 Sepavich et al. is Feb, 1'7,- 1948 2,531,944 Metoal-f -i Nov. 28, l90 2,569,442 Anderson Oct. 2, 1951 

